Loud-speaking receiver



March 27; 192 1,664,012 s. E. WITT 1 LOUD SPEAKING RECEIVER Filed Aug. 12. 1924 I v 2 Sheets-Sheet? liififilliil igwlmlwli'l Patented Mar. 27, 1928.

SAMUEL E. WIT'I, OF CHICAGO, ILLINOIS.

Loon-SPEAKING new.

Application filed August 12, 1924. Serial No. 731,693.

My invention relates to receivers and more particularly to loudspeaking recervers of the type now generally employed In connection with radio apparatus, although 6 of course, it is to be understood that it may be employed for. any telephonic purpose where devices of this kind are employed.

An objectof an improved and simplified receiver'of the 10 character shown 1n mycopending application for receiver. Serial Number 440,549, filed January 27,1921, being of the so called direct current type. 1

There are various features to my inven-' 1 tion, such as an improved adjustment for the magnet and armature carrying unit;

the spool or co1l construction; the unit cn-- struction; the method of locking the unit carrying frame to thebase; the method of 90 locking the cover to the base and of securing the horn to the device. There are various other features and these will be more particularly pointed out in the ensuing part of the specification and appended claims.

2 For a better understanding of my invention reference is to be had to the accompanying drawings, in which- Fig. 1 device with acover and horn carrying parts 0 in section to show the interior; i

Fig. 2 is a sectional view through the re- 4 ceiver mechanism, also showing the method of locking the frame to the base;

Fig. 3 is a perspective detail view of the base lock and terminal carrying element;

Fig. 4 is an enlarged plan view of the coils and armature su porting bracket,

Fig. 5 is a sectiona view along the line 5-5 of Fig. 4.;

Fig. 6 is a side elevation of the apparatus unit removed from the cover with parts of the frame broken away;

Fig. 7 is a bottomview of Fig. 6, but

with-the base plate removed;

,Fig. 8 is a top plan view of Fig. 6;

Fig. 9 is a right end view of Fig. 6; and

Fig. 10 is a left end view of Fig. 61 Referring now more in detail to the pre-' ferred form of my invention as shown herein, it comprises a diaphragm holding'member 15 made of suitable non-magnetic ma terial and cupped so as to receive a diaphragm 17 and held in place by a metal ring 18 '55. forced into the recess. The .metal along the my invention is to provide as a unit. To attach strike up from the base plate 23 is a side elevation of the assembled element so that the arm 29 is lating plate 16 between cushioning rubber rings edge of the en is then pressed inwardly in a suitable num er of places 19, as indicated in Fig. 7, so as to hold the ring 18 and diaphragm in p1 ce. Y

A suitable. ame for supportin the diaphragm cup 15 is provided, pre erably' in the form of two-legged members of similar construction. each one comprising two vertical legs 20 with the yoke pprtion 21 connectingthe legs at the bottom and said legs' being turned outwardly at the top and suitably secured to the diaphragm cup 15. pref erably by rivets cup 15 and leg members 20 form' a substan-- tial base for carrying all of the apparatus this unit to the base I preferablya lug or clamp member 24 (Fig. 2), so shaped that the yoke portion 21 of the frame will slide tightly beneath this lug 24. Thus the two legs of the frame have their yoke portions 21 slid under the lugs 24 to abut the shoulders 25. Now in order to re tain the frame on the base plate I provide a locking member, shown in detail in Fig. 3,

formed up of a piece of sheet metal with upwardly extending ears 26 adapted to snugly fitbetween. the legs 20. This locking element is then secured to the frame by a pin 27 which passes through the holes 28 in the ears 26 and corresponding holes in the legs of the frame. A downwardly extending arm 29 of this locking member rests against abut the edges of the legs 20, the parts being 'so proportioned that with the shoulder 30 against the edges of the legs, the arm 29 7 must beslightly sprung to insert the pin 27 and thus the unit the is securely held to base. I

only necessary to withdraw. the pin 27, thereby permitting a tilting of the locking freed of the lug 24 sufliciently to permit sliding the frame out of the lug from the. base plate 23.

This locking member also carries the attaching terminals for the device, being provided with an arm,31 to which an insu- 32is' secured by rivets 33 (Fig.

2). Terminal plates 34 are insulatingly attached to the insulating sheet 32 by suitable eyelets 3 5, but which rivets do not touch the 22. Thus the diaphragm the inner face 'of the lug 24. The loekingy member has shoulders. 30 which To remove the unit from the base it is 24 and removing it metal arm 31 which has clearance holes 36 therein, as shown in Fig. 7. These terminal plates 34 carry binding screws 37 the i plates being notched at 38 to take a round terminal clip or a spade clip may be inserted between the screw 37 and plate 34.

Referring now to the. diaphragm operating mechanism, this is preferably bullt up in a self-contained unit the parts of which are preferably supported upona frame adjustably carried by the diaphragm carrying frame. This mechanism frame consists of an elon ated U-shaped member having sides 39-40 ent up from the base portion 41.

These sides 39-40 fit snugly between the legs 21 of the main frame and are adjustably held inthe frame by a pivot mounting in the form of a pin 42 which passes through move '11 the frame legs and the sides 39-40. Thus the left end of the pivoted frame is free to and down by adjusting the screw 43. .TlllS adjusts the armature and electromagnet so as to vary the air gap. This adjusting screw 43 is threaded at its lower end 44 in the plate 41 ofthe frame so that as thescrew 30 is rotated the frame is correspondingly moved up and down.- The screw 43 carries a knurled head 45 which is outside the casing, as indicated in Fig. 1, a soft felt Washer 46 being interposed be-= tween the washer 47 carried by the screw 43 and the casing so as to provide a dust proof hole through which the screw 43 extends. This adjusting screw 43 provides a safety adjustment in that in threading the, screw into the plate 41 it stops when the shoulder of the screw abuts the plate. 41, limiting the adjustment in one direction. When the screw 43 is rotated in the other direction it moves the plate 41 downwardly, thereby increasing the air gap at the arma ture, butthis adjustment is limited in that it is so proportioned that thescrew threads out of the plate at the desired limit of adju'stment and simply rotates against the end of the plate-without any further movement thereof.

v The mechanism frame isheld under ten- Sion by a sprin 48 secured underneath the{ plate 41 of the ralne and resting upon a pin 49 extending through the frame legs 20.

Now as to the dia hragm operating mechanism, this is pre erably in the form of a so-called direct current electromagnet, that is one in which no permanent magnet is .em-' ployed. To this end I preferably provide ,two spools or coils preferably connected-in series and made up 1n the form of a uni i ltio'. e.

coils are preferably similar. units, eaehfcom be attached to the adjusting frame.

prising a combination core and heel piece struck up out of a single sheet. of suitable metahthe core 50 being sheared; up out of the body between the two fastening cars 51 i and the downturned portion 52 beingprovided as heel pieces by which the two cores are riveted together. In building up these coils, each core element is taken separately and appropriate spool headsforced thereon, after which the wire is wound on the core. The paired spools are then fastcned'together by rivetin .the heel pieces 52 together so as to. form t e single unit which is then attached to the bottom plate 41 by screws 53, the spools extending up through an opening 54 in the bottom plate'41. The coils are so wound as to present opposite poles at the free or armature ends of the cores, the ends of the wlndings extending through the bottom heads and being connected together and to the-terminals 34, as is more clearly indiment thereof. A pin 57 is swaged upon the end of the armature and is c'ohnected to the diaphragm 16 by a threaded link 58- having an eyelet at its lower end through which the in 57 extends. This link 58 armature .55 and prevent-transverse move- 7 .passesup t rough the diaphragm 16 and;

has a washer and nut on each side of the diaphragm to clamp the link preferably rigidly thereto. Suitable adjustment, of course, is iven to secure proper connection ,between t e armature and diaphragm. I-

'then preferably place a light coating of a suitable "hard wax at the connection between pin 57 and the eyelet, to provide a tight connection.

As I do 'not depend upon a permanent magnet to give a normal fiexure to'thefdia phragm 16, I provide a tension spring, 59 whichholds the armaturein operative rebow the same. ,This spring 59 is preferably adjustable and is riveted to a rocker arm 60 :pivotally supported between the frame sides 39-40 by a pin 61 which is held under the Ill Ill lation to the electromagnet and also laces a tension upon the diaphragm to slightly rear end of the spring 59t0 keep it fromcoming out. In order to adjust the spring 59 I provide a screw 62 threaded through the plate 41 and arm 63 of the magnet frame,

the arm 63. being sprung 'sligh'tly 'after'the parts '63-40 are threaded. so as to force the threads in these two parts out of normal alignment.

threaded therein it. is frictionally held by- Then when the screw 62 is the springing bf the frame. This screw-'62 1 engages the rockerarm 60 so that as the screw is moved one way or. the other the arm 60 is adjusted up and down to 'correspondingly adjustthe tension of the springshape to enclose'the apparatus, the form.

frame carries the .electromagnet and associated armature, together with the corresponding tension spring 59, so that this entire' piece of apparatus may be adjusted as a' unit to vary the air gap of the electromagnet and the spring 59 may be independently adjusted to vary the tension on the armature and fiexure of the diaphragm.

To attach the born to the device I provide a novel arrangement in the form of a cup 64 which threads into the neck of the diaphragm cup 15.. The neck of thehorn 65 is provided with a sleeve 66 suitably secured thereto, after the lock nut 67 is placed on the neck of the horn. A soft gasket 68 is placed in the bottom of the cup 64 and the neck of the horn inserted in the cup. The lock nut 67 is'then threaded onto the cup 64, engaging the upper shoulder on the sleeve 66, so as to hold the horn rigidly in place.

I'also provide a novel means for securing a cap or cover over the mechanism, to this end providing the cover 69 which is formed up of a suitable material and of the proper.

shown being circular. This cover 69 sets down into the upturned peripheral flange of terminal plates at course,'the cup 64 is out 7 the casing 69 to 'gether by passing the the cup 64 to engage 245 is taken off before the casing the base plate 23, the parts being held tohorn holding c up 64 having a shoulder on the cover and hold, it in place as the cup is screwed into the diaphragm can 15. The cover 69-is also provided with a pair of openings through which the terminal plates 34 pass, these openings each having a soft rubber bushing 7 Oto insulate the terminal plates 34 and prevent contact with the cover.

'Itwill be noted that the adjusting-screw 43-has an operating knob 45 threaded thereon on the outside of'the casing 69. In order to assemble these parts in this way the knob 69 is applied, also belng out of the this time. Also, of of the casing 69. The casing is then passed over the top of the apparatus with the adjusting screw 43 extending up through the casing. A pair through the cover and the terminal screws 67 -of pliers or suitable instruments is then the opening at the top of ras the shank of the ad.- justin screw 43 while the nut 45 is being threa ed and set thereon. The nut 45' is preferably set tight enou h so: that it will not readily thread off in a usting-the device.

slipped through The cup 64 is then passed through the casing then'eck of the diaterminal screws 37 69 and threaded into phragm cap. 5 Also the 'ratus of this kind to rubber washer or elongated frame have a device completely enclosed and practically dust-proof and fool-proof, as when assembled in this way it is not readily discovered how to take it apart.- This is most desirablein connection with a piece of appakeep those unfamiliar with its construction from gaining access to the interior and disturbing the proper adjustment of the parts,

In the use of the device after being normally adjusted it may be adjusted by simply varying the armature adjustment through the use of the exterior adjusting nut 45. This gives a range suitable for ordinary use with different circuits. L

What I claim as new and desire to secure by Letters Patent is:

1. In a receiver, a diaphragm and mounting therefor, an electromagnet' and an armature therefor connected to the diaphragm, a springyieldingly holding the armature under tension, means for adjusting the spring tension independent of variation of adjustment of the-armature, a frame for the elecsaid mounting, and'means for adjusting the mounting on, its'pivotto move the electromagnet to vary the air gap between the armature and electromagne't.

2. In a receiver, a diaphragm and mounting therefor, an electromagnet and "an artromagnet pivotally supported at one end by mature therefor connected to the diaphragm,

a frame for the electromagnet pivotally supported at one end by said mounting, a spring adjustably carried with the fgam acting upon the armature to press it to ard the electromagnet and flex the diaphragm, and

means for adjusting the mounting on-its pivotto move the electromagnet to vary the air gap between the armature and electromagnet. i

3. In a receiver, a diaphragm and mounting therefor, an el'ectromag'net and an armature therefor connected to the diaphragm, a

frame for the electromagnet pivotally supported at one end by said mounting, a spr ng adjustably carried with the frame actln'g upon the. armature topressvit toward the c 0 electromagnet and flex the diaphragm, and means for adjusting the mounting on its the. armature and electrobetween the pivot to move the electromagnet to vary the air gap 4. In a receiver, a diaphragm and mounting therefor, therefor connected to the diaphragm, an

for, carrying the electromagnet pivotally supported at one end by said mounting and an adjusting screw conmagnet, said adjusting'screw and mounting an electromagnet and armature nected to the other. end of the framefor tilting the frame on ts p vot to vary the l air gap between the armature and electroand cooperating to limit the extentof adjustmerit of the frame in both directions.

5. In. a receiver, a diaphragm operating 'electromagnet and armature, a sheet metal frame for the electromagnet, an armature tension spring carried by said frame, said frame having two, relatively 'yieldable plates tipped in a normal. relation and then sprung to an abnormal relation,'and an adjusting screw for the tension spring threaded through the-frame plates while sprung back.

to a nomal position to frictionally hold the adjusting screw in a set position.

6. In a receiver, a diaphragm and supporting cup therefor, and operating mechanism' for the diaphragm comprising an elongated U-shaped frame pivotally attached at one end to the supporting cup and having an adjusting screw operatively connected to the other end so as to adjust the frame toward and away from the diaphragm, an electromagnet secured to the base of the frame between its sides, and an armature for the electromagnet pivotally supported at one end and having its other end. connected to the diaphragm. v,

7. In a receiver, adiaphragm and supporting cup therefor, and operating mechani-sm for the diaphragm comprising an'elongated U-shaped frame. pivotally attached at one end to the supporting cup and having so I an adjusting screw operatively connected to the-other end so as to-adjust the frame toward andfaway from the diaphragm, an

electromagnet secured to the base of the leaving two right angle ears extending to one side of the core and a portion of the sheet metal extending from the other side of the core and then bent downwardly to form a heel piece, said down turned portions of a pair being turned toward each other' and permanently secured together to forma unitary structure.

In witness whereof, I hereunto subscribe my name this 8 day of July, 1924. i

SAMUEL E. WITT. 

